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Re: Centrino CpuFreq

Hi Li,

Jochen Schulz schrieb:

> * =?gb18030?Q?=C0=EE=D1=E5_Li_Yan?=:
> >
>> My T42's CPU can run @221Mhz under windowsXP,
>> >
> How do you tell? Do you use something like SpeedswitchXP?
> >
>> but with powersave governer provided by Linux 2.6.9, it's
>> cpuinfo_min_freq is 600Mhz.  Any ideas?
>> I found a similar issue when I accidently loaded the "wrong" cpufreq driver for P4 with powernowd. Suddenly /proc/cpuinfo showed frequencies down to 200 MHz (the Bogomips also went down). So I searched a little bit. People seem to think that those 600Mhz is kind of hardcoded to the Centrino chipset. Taking a closer look to the Intel Docu I found that the Intel specifications seem to be merely recommendations. Other combinations of Frequency and Voltage are possible. The docu regarding voltages clearly shows that there are voltages possible other than those in the Freq/Voltage table.

I got curious and played around a little bit: On my centrino I could lower the frequency down to 100 Mhz. Lower frequencies caused the cpuinfo display to be messed, but frequency down to 100Mhz seem to be stable. To be clear: Those tricks are not official language! But my accu now works conspiciously longer :-) I do not know wether this can cause some damage so I cannot recommend doing such things.

Best regards

  Dieter Jäger

> I think Windows may lie to you. As far as I know Centrinos cannot run on
> lower clockspeeds than 600MHz.
> J.
> >

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